What’s better than one Wavetrac? Two!
That’s right, for this 8N TT we will be installing not one but two Wavetrac differentials! Whatsmore is that this TT is equipped with the DQ250 making this install a little more in-depth than a conventional manual installation. With both boxes removed from the TT and on the bench, let’s get started with the Wavetrac install…
Firstly we remove the factory open rear differential and install the rear Haldex Wavetrac ATB LSD. Wavetrac offers an upgrades ATB LSD for the rear Haldex units in the 8N TT Quattro, S3 Quattro and MK4 Golf 4 Motion models.
So what exactly is a Wavetrac ATB LSD? Wavetrac is a unique Automatic Torque Biasing Limited Slip Differential that outperforms all other ATB LSDs on the market thanks to its patented design features.
So, what exactly is the problem that an ATB LSDs solves? A factory open differential (pictured above) has a bias ratio of 1:1. This means that once traction is lost and a wheel is slipping, all drive torque is biased to the slipping wheel. This halts acceleration due to all of the torque being sent to the wheel with the least grip, spinning aimlessly until traction is regained by coming off of the accelerator or using the brakes to slow the wheel down (this is how electric differentials work).
With the Wavetrac ATB LSD power is biased away from the wheel with the least grip, to the wheel with the most traction. Where the Wavetrac ATB LSD comes into its own is when axle load is lost, for example by wheel slip, lift or suspension unloading (cornering). Under these conditions, all other ATB LSDs function like an open differential sending torque to the wheel with the least traction.
Thanks to Wavetrac’s patented design, specifically the “wave hub” it can create load internally in these situations by reacting to a difference in axle speed. In this situation, the wave hub begins to ramp and create enough internal load to maintain drive. Conditions this is beneficial is in all situations where you are close to the traction limit (spirited driving), wet weather, bumpy roads or curbs at the track and many others.
Wavetrac information overload? Let’s move on and show you around a Dual Clutch DQ250 gearbox commonly found in the DSG equipped MK4/5/6/7 Golf models. In these images, you can see how the gearbox changes gears. Firstly the mechatronic unit sends oil through the various galleries which are routed throughout the multiple casings and eventually into a plunger which moves a selector. Simple, effective and super fast!
Once the stock open differential is removed the rivets holding the diff and crown wheel are removed and replaced with the supplied ARP bolts.
At the same time, we replace the internal DSG filter. The DSG DQ250 has an internal filter only accessible by opening up the casing and another filter for easy access service use on the outside. On a higher mileage model like this, it’s certainly beneficial to change!
With both the front and rear differentials upgraded to the Wavetrac ATB LSD its fair to say that this 8N TT DSG V6 will have tonnes of traction in any situation…